They said
A message has balanced parentheses if it consists of one of the following:

- An empty string ""
- One or more of the following characters: 'a' to 'z', ' ' (a space) or ':' (a colon)
- An open parenthesis '(', followed by a message with balanced parentheses, followed by a close parenthesis ')'.
- A message with balanced parentheses followed by another message with balanced parentheses.
- A smiley face "" or a frowny face ""

SO if any of those statement is true, It will be balanced.

But they said ( is not balanced, but is satisfy the last term. So why it is not balanced?